Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Starter Signal Circuit Test: GS300
Remove ECM hood and cover, and locate ECM. See COMPONENT LOCATIONS . Using DVOM, backprobe ECM 28-pin connector E5 terminal No. 2 (Black wire). See Fig 1. Check for voltage with ignition in START position. If voltage is 6 volts or more, ECM is okay. If voltage is less than 6 volts, check for open in wiring harness or connectors between ECM and starter relay. Repair as necessary. If wiring harness and connectors are okay, replace ECM.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.